1. Field of Invention
This invention generally relates to a method and apparatus for monitoring and treating sleep disorders, and, more particularly, to a computerized polysomnographic system for simultaneously monitoring a plurality of patients undergoing respective sleep studies and for controlling a pressure support device for each individual patient, either treating a patient or for determining a prescription for treatment of a patient having a breathing disorder, such as sleep apnea.
2. Description of Related Art
There are three recognized types of sleep apnea. Central sleep apnea is characterized by the suspension of all respiratory movement and is generally believed to be neurological in origin. Obstructive sleep apnea is characterized by the collapse of the upper airways during sleep. The third type of sleep apnea is a combination of central and obstructive sleep apnea and is known as mixed apnea. Individuals having sleep apnea often are only able to sleep for short periods of time before interruption by apneic episodes and, therefore, are only able to obtain fragmented and intermittent sleep. As a result, sleep apnea can cause a host of secondary symptoms, such as general fatigue and daytime sleepiness, high blood pressure, cognitive dysfunction, cardiac arrhythmia, and even congestive heart failure. It is estimated that between 1% and 5% of the general population are afflicted with some level of sleep apnea.
Treatments for sleep apnea have included a number of pharmacological agents and several surgical procedures such as tracheostomy or the removal of excess muscle and tissue from the tongue or airway walls. However, pharmacological treatments for sleep apnea have been generally ineffective and may have adverse side effects. Furthermore, the surgical procedures involve major surgery which may cause extreme discomfort and may involve significant risk of postoperative complications.
Another, less invasive and more effective method for treating obstructive sleep apnea involves the use of continuous positive airway pressure (xe2x80x9cCPAPxe2x80x9d) to prevent obstruction of the patient""s airway during sleep. In CPAP, air is generally provided to the patients airway via a nasal mask at a selected pressure or pressures. If too much air is provided, the patient will experience discomfort and is likely to discontinue the treatment. If too little air is provided, the occlusion will not be prevented from occurring and the patient will continue to experience apneic episodes.
Accordingly, it is usually necessary to perform a calibration in order to determine the therapeutic delivery of gas pressure and gas flow provided to each patient who is to receive nasal-CPAP treatment. Calibration is generally performed by a sleep technician as a part of a sleep study of the patient. During the sleep study, the technician monitors a number of the patient""s physiological parameters via a polysomnographic device and manipulates the operating parameters of nasal-CPAP device in response to the data sensed by a in order to optimize the parameters for the specific patient if obstructive sleep apnea appears to occur. Typically, the technician observes the individual being treated with the nasal-CPAP treatment and manipulates the airflow and pressure from the nasal-CPAP device to progressively increase it until no further breathing abnormalities or other evidence of upper airway occlusions or resistance are observed. Sleep studies also may be performed to investigate and diagnose the sleep behavior of individuals who are suffering from other sleeping disorders.
During a sleep study, a polysomnographic device is used to monitor certain of the individual""s physiological parameters to allow a determination of whether the individual suffers from any physiological impairment that hinders the individual""s sleep pattern. Typically, the monitored parameters include such things as electrical encephalographic activity (EEG); eye movements, muscle activity, heart rhythm (ECG), respiratory effort, nasal and/or oral airflow, blood oxygen saturation (SpO2), body position, limb movements, exhalation CO2, esophageal pH; and breathing sounds (for snoring). These parameters are typically each monitored by sensors that produce analog signals which are then transmitted to a control/display unit for presentation to a sleep technician.
An example of a polysomnographic device is the Alice(copyright) 3 polysomnographic system developed by Respironics, Inc. of Pittsburgh, Pa. The Alice(copyright) 3 system incorporates a number of sensors attached to a sensor input box. The signals are transferred to an amplifier which amplifies, conditions and digitizes the signals. From the amplifier, the digital signals are sent to a standalone computer wherein software displays the signals in a manner designated by a sleep technician. From the signals, sleep disorders are diagnosed. After the airway becomes obstructed, the obstruction is usually not relieved until the individual arouses from sleep. A typical polysomnographic system, such as the Alice(copyright) 3 system, can only be used to monitor the parameters of a single patient.
During the therapeutic stage of the sleep study, while the polysomnographic apparatus monitors and displays the sleep information from the individual if obstructive sleep apnea appears present, a sleep technician is required to attend each individual patient in order to manipulate an independent nasal-CPAP device in conjunction with monitoring the polysomnographic apparatus and observe the impact of the manipulation of various pressures induced by the nasal-CPAP device. This situation, while suitable for its intended purpose, results in the need for a one-to-one ratio of sleep technicians and sleep patients. However, because sleep studies are often performed in hospitals and sleep labs, which are typically conducting multiple simultaneous studies, it would be desirable to decrease the number of sleep technicians required in order to reduce the overall operating costs of the sleep study facility. Thus, there is a need for a system allowing a single sleep technician to perform simultaneous sleep studies on multiple patients.
Accordingly, it is an object of the present invention to provide a polysomnographic apparatus that enables a single technician to conduct multiple sleep studies simultaneously.
Furthermore, it is an object of the present invention to provide a polysomnographic apparatus that enables a single technician to monitor sleep related data from several patients simultaneously while also being able to control the operation of a positive pressure support device for each individual patient for diagnosing obstructive sleep apnea or determining a therapeutic prescription for treating an obstructive sleep apneic occurrence.
It is yet another object of the present invention to provide a polysomnographic apparatus that may be used by a sleep technician to monitor and adjust the therapy of one or more patients who are sited at remote locations.
The above objectives are accomplished according to the present invention by providing a polysomnographic system for use in conjunction with a communications network. The polysomnographic system includes a first remote unit for collecting physiological data from a first patient. The first remote unit includes a first sensor for detecting a physiological parameter of the first patient and generating a first parameter indicating signal in response thereto, which is communicated to the communications network via a first communications interface. The polysomnographic system also includes a second remote unit for collecting physiological data from a second patient. The second remote unit includes a second sensor for detecting a physiological parameter of the second patient and generating a second parameter indicating signal in response thereto, which is communicated to the communications network via a second communications interface. The polysomnographic device includes a host unit for receiving the first and second parameter indicating signals via the communication network and for displaying information indicative of the first and second parameters to an operator.